Multi-task recurrent neural network architecture for efficient morphology handling in neural language modeling

ABSTRACT

The present disclosure generally relates to systems and processes for morpheme-based word prediction. An example method includes receiving a current word; determining a context of the current word based on the current word and a context of a previous word; determining, using a morpheme-based language model, a likelihood of a prefix based on the context of the current word; determining, using the morpheme-based language model, a likelihood of a stem based on the context of the current word; determining, using the morpheme-based language model, a likelihood of a suffix based on the context of the current word; determining a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix; and providing an output including the next word.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application Ser. No. 62/514,454, entitled “MULTI-TASK RECURRENT NEURAL NETWORK ARCHITECTURE FOR EFFICIENT MORPHOLOGY HANDLING IN NEURAL LANGUAGE MODELING,” filed Jun. 2, 2017, the content of which is hereby incorporated by reference in its entirety for all purposes.

FIELD

The present disclosure relates generally to word prediction, and more specifically to techniques for morpheme-based word prediction.

BACKGROUND

The occurrence of word inflection raises certain challenges in the context of word predictions using particular language models, such as n-gram language models. Word inflection refers to the modifying of words to encode grammatical information such as tense, number, gender, and so forth. For example, English inflects regular verbs for past tense using the suffix “ed” (as in “talk”→“talked”). Other languages can exhibit higher levels of word inflection. Romance languages, such as French, have more overt inflection due to complex verb conjugation and gender declension. Agglutinative languages, such as Finnish, have even higher levels of inflection, as a separate inflected form may be needed for each grammatical category.

While one conventional solution to this problem has been to partition words according to morphological information, such approaches do not parsimoniously translate to recurrent neural network language models (RNNLMs) due to the separate histories required for each stem and suffix category considered during operation.

BRIEF SUMMARY

Example methods are disclosed herein. An example method includes, at an electronic device having one or more processors, receiving a current word; determining a context of the current word based on the current word and a context of a previous word; determining, using a morpheme-based language model, a likelihood of a prefix based on the context of the current word; determining, using the morpheme-based language model, a likelihood of a stem based on the context of the current word; determining, using the morpheme-based language model, a likelihood of a suffix based on the context of the current word; determining a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix; and providing an output including the next word.

An example method includes receiving a current word representation, wherein the current word representation includes a current prefix representation, a current stem representation, and a current suffix representation; determining a current word context based on the current word and a previous word context; determining a next word representation based on the current word context, wherein the next word representation includes a next prefix representation, a next stem representation, and a next suffix representation; and providing the next word representation.

Example non-transitory computer-readable media are disclosed herein. An example non-transitory computer-readable storage medium stores one or more programs. The one or more programs comprise instructions, which when executed by one or more processors of an electronic device, cause the electronic device to receive a current word; determine a context of the current word based on the current word and a context of a previous word; determine, using a morpheme-based language model, a likelihood of a prefix based on the context of the current word; determine, using the morpheme-based language model, a likelihood of a stem based on the context of the current word; determine, using the morpheme-based language model, a likelihood of a suffix based on the context of the current word; determine a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix; and providing an output including the next word.

An example non-transitory computer-readable storage medium stores one or more programs. The one or more programs comprise instructions, which when executed by one or more processors of an electronic device, cause the electronic device to receive a current word representation, wherein the current word representation includes a current prefix representation, a current stem representation, and a current suffix representation; determine a current word context based on the current word and a previous word context; determine a next word representation based on the current word context, wherein the next word representation includes a next prefix representation, a next stem representation, and a next suffix representation; and provide the next word representation.

Example electronic devices are disclosed herein. An example electronic device comprises one or more processors; a memory; and one or more programs, where the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for receiving a current word; determining a context of the current word based on the current word and a context of a previous word; determining, using a morpheme-based language model, a likelihood of a prefix based on the context of the current word; determining, using the morpheme-based language model, a likelihood of a stem based on the context of the current word; determining, using the morpheme-based language model, a likelihood of a suffix based on the context of the current word; determining a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix; and providing an output including the next word.

An example electronic device comprises one or more processors; a memory; and one or more programs, where the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for receiving a current word representation, wherein the current word representation includes a current prefix representation, a current stem representation, and a current suffix representation; determining a current word context based on the current word and a previous word context; determining a next word representation based on the current word context, wherein the next word representation includes a next prefix representation, a next stem representation, and a next suffix representation; and providing the next word representation.

An example electronic device comprises means for receiving a current word; means for determining a context of the current word based on the current word and a context of a previous word; means for determining, using a morpheme-based language model, a likelihood of a prefix based on the context of the current word; means for determining, using the morpheme-based language model, a likelihood of a stem based on the context of the current word; means for determining, using the morpheme-based language model, a likelihood of a suffix based on the context of the current word; means for determining a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix; and means for providing an output including the next word.

An example electronic device comprises means for receiving a current word representation, wherein the current word representation includes a current prefix representation, a current stem representation, and a current suffix representation; means for determining a current word context based on the current word and a previous word context; means for determining a next word representation based on the current word context, wherein the next word representation includes a next prefix representation, a next stem representation, and a next suffix representation; and means for providing the next word representation.

Determining a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix allows for the concurrent determination of prefixes, stems, and suffixes of a next word based on a current word and/or the context of the current word. Determining in this manner is made possible by eliminating the separate word histories required for stems and suffixes and applying morpheme-based language prediction to RNNLMs. As a result, an electronic device may perform word prediction more quickly, efficiently, and accurately.

Determining a next word representation based on the current word context, wherein the next word representation includes a next prefix representation, a next stem representation, and a next suffix representation allows for the concurrent determination of prefixes, stems, and suffixes of a next word based on a current word and/or the context of the current word. Determining in this manner is made possible by eliminating the separate word histories required for stems and suffixes and applying morpheme-based language prediction to RNNLMs. As a result, an electronic device may perform word prediction more quickly, efficiently, and accurately.

DESCRIPTION OF THE FIGURES

For a better understanding of the various described embodiments, reference should be made to the Description of Embodiments below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures.

FIG. 1A is a block diagram illustrating a portable multifunction device with a touch-sensitive display in accordance with some embodiments.

FIG. 1B is a block diagram illustrating exemplary components for event handling in accordance with some embodiments.

FIG. 2 illustrates a portable multifunction device having a touch screen in accordance with some embodiments.

FIG. 3 is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments.

FIG. 4A illustrates an exemplary user interface for a menu of applications on a portable multifunction device in accordance with some embodiments.

FIG. 4B illustrates an exemplary user interface for a multifunction device with a touch-sensitive surface that is separate from the display in accordance with some embodiments.

FIG. 5A illustrates a personal electronic device in accordance with some embodiments.

FIG. 5B is a block diagram illustrating a personal electronic device in accordance with some embodiments.

FIG. 6 illustrates an exemplary block diagram of a text prediction system in accordance with some embodiments.

FIG. 7 illustrates a text prediction network in accordance with some embodiments.

FIG. 8 is a flow diagram of a process for text prediction in accordance with some embodiments.

FIG. 9 is a flow diagram of a process for text prediction in accordance with some embodiments.

DESCRIPTION OF EMBODIMENTS

The following description sets forth exemplary methods, parameters, and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure but is instead provided as a description of exemplary embodiments.

Although the following description uses terms “first,” “second,” etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first text input could be termed a second text input and, similarly, a second text input could be termed a first text input, without departing from the scope of the various described embodiments. The first text input and the second text input are both text inputs, but they are not the same text input.

The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The term “if” is, optionally, construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” is, optionally, construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context.

Embodiments of electronic devices, user interfaces for such devices, and associated processes for using such devices are described. In some embodiments, the device is a portable communications device, such as a mobile telephone, that also contains other functions, such as PDA and/or music player functions. Exemplary embodiments of portable multifunction devices include, without limitation, the iPhone®, iPod Touch®, and iPad® devices from Apple Inc. of Cupertino, Calif. Other portable electronic devices, such as laptops or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and/or touchpads), are, optionally, used. It should also be understood that, in some embodiments, the device is not a portable communications device, but is a desktop computer with a touch-sensitive surface (e.g., a touch screen display and/or a touchpad).

In the discussion that follows, an electronic device that includes a display and a touch-sensitive surface is described. It should be understood, however, that the electronic device optionally includes one or more other physical user-interface devices, such as a physical keyboard, a mouse, and/or a joystick.

The device typically supports a variety of applications, such as one or more of the following: a drawing application, a presentation application, a word processing application, a website creation application, a disk authoring application, a spreadsheet application, a gaming application, a telephone application, a video conferencing application, an e-mail application, an instant messaging application, a workout support application, a photo management application, a digital camera application, a digital video camera application, a web browsing application, a digital music player application, and/or a digital video player application.

The various applications that are executed on the device optionally use at least one common physical user-interface device, such as the touch-sensitive surface. One or more functions of the touch-sensitive surface as well as corresponding information displayed on the device are, optionally, adjusted and/or varied from one application to the next and/or within a respective application. In this way, a common physical architecture (such as the touch-sensitive surface) of the device optionally supports the variety of applications with user interfaces that are intuitive and transparent to the user.

Attention is now directed toward embodiments of portable devices with touch-sensitive displays. FIG. 1A is a block diagram illustrating portable multifunction device 100 with touch-sensitive display system 112 in accordance with some embodiments. Touch-sensitive display 112 is sometimes called a “touch screen” for convenience and is sometimes known as or called a “touch-sensitive display system.” Device 100 includes memory 102 (which optionally includes one or more computer-readable storage mediums), memory controller 122, one or more processing units (CPUs) 120, peripherals interface 118, RF circuitry 108, audio circuitry 110, speaker 111, microphone 113, input/output (I/O) subsystem 106, other input control devices 116, and external port 124. Device 100 optionally includes one or more optical sensors 164. Device 100 optionally includes one or more contact intensity sensors 165 for detecting intensity of contacts on device 100 (e.g., a touch-sensitive surface such as touch-sensitive display system 112 of device 100). Device 100 optionally includes one or more tactile output generators 167 for generating tactile outputs on device 100 (e.g., generating tactile outputs on a touch-sensitive surface such as touch-sensitive display system 112 of device 100 or touchpad 355 of device 300). These components optionally communicate over one or more communication buses or signal lines 103.

As used in the specification and claims, the term “intensity” of a contact on a touch-sensitive surface refers to the force or pressure (force per unit area) of a contact (e.g., a finger contact) on the touch-sensitive surface, or to a substitute (proxy) for the force or pressure of a contact on the touch-sensitive surface. The intensity of a contact has a range of values that includes at least four distinct values and more typically includes hundreds of distinct values (e.g., at least 256). Intensity of a contact is, optionally, determined (or measured) using various approaches and various sensors or combinations of sensors. For example, one or more force sensors underneath or adjacent to the touch-sensitive surface are, optionally, used to measure force at various points on the touch-sensitive surface. In some implementations, force measurements from multiple force sensors are combined (e.g., a weighted average) to determine an estimated force of a contact. Similarly, a pressure-sensitive tip of a stylus is, optionally, used to determine a pressure of the stylus on the touch-sensitive surface. Alternatively, the size of the contact area detected on the touch-sensitive surface and/or changes thereto, the capacitance of the touch-sensitive surface proximate to the contact and/or changes thereto, and/or the resistance of the touch-sensitive surface proximate to the contact and/or changes thereto are, optionally, used as a substitute for the force or pressure of the contact on the touch-sensitive surface. In some implementations, the substitute measurements for contact force or pressure are used directly to determine whether an intensity threshold has been exceeded (e.g., the intensity threshold is described in units corresponding to the substitute measurements). In some implementations, the substitute measurements for contact force or pressure are converted to an estimated force or pressure, and the estimated force or pressure is used to determine whether an intensity threshold has been exceeded (e.g., the intensity threshold is a pressure threshold measured in units of pressure). Using the intensity of a contact as an attribute of a user input allows for user access to additional device functionality that may otherwise not be accessible by the user on a reduced-size device with limited real estate for displaying affordances (e.g., on a touch-sensitive display) and/or receiving user input (e.g., via a touch-sensitive display, a touch-sensitive surface, or a physical/mechanical control such as a knob or a button).

As used in the specification and claims, the term “tactile output” refers to physical displacement of a device relative to a previous position of the device, physical displacement of a component (e.g., a touch-sensitive surface) of a device relative to another component (e.g., housing) of the device, or displacement of the component relative to a center of mass of the device that will be detected by a user with the user's sense of touch. For example, in situations where the device or the component of the device is in contact with a surface of a user that is sensitive to touch (e.g., a finger, palm, or other part of a user's hand), the tactile output generated by the physical displacement will be interpreted by the user as a tactile sensation corresponding to a perceived change in physical characteristics of the device or the component of the device. For example, movement of a touch-sensitive surface (e.g., a touch-sensitive display or trackpad) is, optionally, interpreted by the user as a “down click” or “up click” of a physical actuator button. In some cases, a user will feel a tactile sensation such as an “down click” or “up click” even when there is no movement of a physical actuator button associated with the touch-sensitive surface that is physically pressed (e.g., displaced) by the user's movements. As another example, movement of the touch-sensitive surface is, optionally, interpreted or sensed by the user as “roughness” of the touch-sensitive surface, even when there is no change in smoothness of the touch-sensitive surface. While such interpretations of touch by a user will be subject to the individualized sensory perceptions of the user, there are many sensory perceptions of touch that are common to a large majority of users. Thus, when a tactile output is described as corresponding to a particular sensory perception of a user (e.g., an “up click,” a “down click,” “roughness”), unless otherwise stated, the generated tactile output corresponds to physical displacement of the device or a component thereof that will generate the described sensory perception for a typical (or average) user.

It should be appreciated that device 100 is only one example of a portable multifunction device, and that device 100 optionally has more or fewer components than shown, optionally combines two or more components, or optionally has a different configuration or arrangement of the components. The various components shown in FIG. 1A are implemented in hardware, software, or a combination of both hardware and software, including one or more signal processing and/or application-specific integrated circuits.

Memory 102 optionally includes high-speed random access memory and optionally also includes non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other non-volatile solid-state memory devices. Memory controller 122 optionally controls access to memory 102 by other components of device 100.

Peripherals interface 118 can be used to couple input and output peripherals of the device to CPU 120 and memory 102. The one or more processors 120 run or execute various software programs and/or sets of instructions stored in memory 102 to perform various functions for device 100 and to process data. In some embodiments, peripherals interface 118, CPU 120, and memory controller 122 are, optionally, implemented on a single chip, such as chip 104. In some other embodiments, they are, optionally, implemented on separate chips.

RF (radio frequency) circuitry 108 receives and sends RF signals, also called electromagnetic signals. RF circuitry 108 converts electrical signals to/from electromagnetic signals and communicates with communications networks and other communications devices via the electromagnetic signals. RF circuitry 108 optionally includes well-known circuitry for performing these functions, including but not limited to an antenna system, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC chipset, a subscriber identity module (SIM) card, memory, and so forth. RF circuitry 108 optionally communicates with networks, such as the Internet, also referred to as the World Wide Web (WWW), an intranet and/or a wireless network, such as a cellular telephone network, a wireless local area network (LAN) and/or a metropolitan area network (MAN), and other devices by wireless communication. The RF circuitry 108 optionally includes well-known circuitry for detecting near field communication (NFC) fields, such as by a short-range communication radio. The wireless communication optionally uses any of a plurality of communications standards, protocols, and technologies, including but not limited to Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), high-speed downlink packet access (HSDPA), high-speed uplink packet access (HSUPA), Evolution, Data-Only (EV-DO), HSPA, HSPA+, HSPA (DC-HSPDA), long term evolution (LTE), near field communication (NFC), wideband code division multiple access (W-CDMA), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Bluetooth Low Energy (BTLE), Wireless Fidelity (Wi-Fi) (e.g., IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, and/or IEEE 802.11ac), voice over Internet Protocol (VoIP), Wi-MAX, a protocol for e-mail (e.g., Internet message access protocol (IMAP) and/or post office protocol (POP)), instant messaging (e.g., extensible messaging and presence protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and/or Short Message Service (SMS), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document.

Audio circuitry 110, speaker 111, and microphone 113 provide an audio interface between a user and device 100. Audio circuitry 110 receives audio data from peripherals interface 118, converts the audio data to an electrical signal, and transmits the electrical signal to speaker 111. Speaker 111 converts the electrical signal to human-audible sound waves. Audio circuitry 110 also receives electrical signals converted by microphone 113 from sound waves. Audio circuitry 110 converts the electrical signal to audio data and transmits the audio data to peripherals interface 118 for processing. Audio data is, optionally, retrieved from and/or transmitted to memory 102 and/or RF circuitry 108 by peripherals interface 118. In some embodiments, audio circuitry 110 also includes a headset jack (e.g., 212, FIG. 2). The headset jack provides an interface between audio circuitry 110 and removable audio input/output peripherals, such as output-only headphones or a headset with both output (e.g., a headphone for one or both ears) and input (e.g., a microphone).

I/O subsystem 106 couples input/output peripherals on device 100, such as touch screen 112 and other input control devices 116, to peripherals interface 118. I/O subsystem 106 optionally includes display controller 156, optical sensor controller 158, intensity sensor controller 159, haptic feedback controller 161, and one or more input controllers 160 for other input or control devices. The one or more input controllers 160 receive/send electrical signals from/to other input control devices 116. The other input control devices 116 optionally include physical buttons (e.g., push buttons, rocker buttons, etc.), dials, slider switches, joysticks, click wheels, and so forth. In some alternate embodiments, input controller(s) 160 are, optionally, coupled to any (or none) of the following: a keyboard, an infrared port, a USB port, and a pointer device such as a mouse. The one or more buttons (e.g., 208, FIG. 2) optionally include an up/down button for volume control of speaker 111 and/or microphone 113. The one or more buttons optionally include a push button (e.g., 206, FIG. 2).

A quick press of the push button optionally disengages a lock of touch screen 112 or optionally begins a process that uses gestures on the touch screen to unlock the device, as described in U.S. patent application Ser. No. 11/322,549, “Unlocking a Device by Performing Gestures on an Unlock Image,” filed Dec. 23, 2005, U.S. Pat. No. 7,657,849, which is hereby incorporated by reference in its entirety. A longer press of the push button (e.g., 206) optionally turns power to device 100 on or off. The functionality of one or more of the buttons are, optionally, user-customizable. Touch screen 112 is used to implement virtual or soft buttons and one or more soft keyboards.

Touch-sensitive display 112 provides an input interface and an output interface between the device and a user. Display controller 156 receives and/or sends electrical sign from/to touch screen 112. Touch screen 112 displays visual output to the user. The visual output optionally includes graphics, text, icons, video, and any combination thereof (collectively termed “graphics”). In some embodiments, some or all of the visual output optionally corresponds to user-interface objects.

Touch screen 112 has a touch-sensitive surface, sensor, or set of sensors that accepts input from the user based on haptic and/or tactile contact. Touch screen 112 and display controller 156 (along with any associated modules and/or sets of instructions in memory 102) detect contact (and any movement or breaking of the contact) on touch screen 112 and convert the detected contact into interaction with user-interface objects (e.g., one or more soft keys, icons, web pages, or images) that are displayed on touch screen 112. In an exemplary embodiment, a point of contact between touch screen 112 and the user corresponds to a finger of the user.

Touch screen 112 optionally uses LCD (liquid crystal display) technology, LPD (light emitting polymer display) technology, or LED (light emitting diode) technology, although other display technologies are used in other embodiments. Touch screen 112 and display controller 156 optionally detect contact and any movement or breaking thereof using any of a plurality of touch sensing technologies now known or later developed, including but not limited to capacitive, resistive, infrared, and surface acoustic wave technologies, as well as other proximity sensor arrays or other elements for determining one or more points of contact with touch screen 112. In an exemplary embodiment, projected mutual capacitance sensing technology is used, such as that found in the iPhone® and iPod Touch® from Apple Inc. of Cupertino, Calif.

A touch-sensitive display in some embodiments of touch screen 112 is, optionally, analogous to the multi-touch sensitive touchpads described in the following U.S. Pat. No. 6,323,846 (Westerman et al.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No. 6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1, each of which is hereby incorporated by reference in its entirety. However, touch screen 112 displays visual output from device 100, whereas touch-sensitive touchpads do not provide visual output.

A touch-sensitive display in some embodiments of touch screen 112 is described in the following applications: (1) U.S. patent application Ser. No. 11/381,313, “Multipoint Touch Surface Controller,” filed May 2, 2006; (2) U.S. patent application Ser. No. 10/840,862, “Multipoint Touchscreen,” filed May 6, 2004; (3) U.S. patent application Ser. No. 10/903,964, “Gestures For Touch Sensitive Input Devices,” filed Jul. 30, 2004; (4) U.S. patent application Ser. No. 11/048,264, “Gestures For Touch Sensitive input Devices,” filed Jan. 31, 2005; (5) U.S. patent application Ser. No. 11/038,590, “Mode-Based Graphical User Interfaces For Touch Sensitive Input Devices,” filed Jan. 18, 2005; (6) U.S. patent application Ser. No. 11/228,758, “Virtual Input Device Placement On A Touch Screen User Interface,” filed Sep. 16, 2005; (7) U.S. patent application Ser. No. 11/228,700, “Operation Of A Computer With A Touch Screen Interface,” filed Sep. 16, 2005; (8) U.S. patent application Ser. No. 11/228,737, “Activating Virtual Keys Of A Touch-Screen Virtual Keyboard,” filed Sep. 16, 2005; and (9) U.S. patent application Ser. No. 11/367,749, “Multi-Functional Hand-Held Device,” filed Mar. 3, 2006. All of these applications are incorporated by reference herein in their entirety.

Touch screen 112 optionally has a video resolution in excess of 100 dpi. In some embodiments, the touch screen has a video resolution of approximately 160 dpi. The user optionally makes contact with touch screen 112 using any suitable object or appendage, such as a stylus, a finger, and so forth. In some embodiments, the user interface is designed to work primarily with finger-based contacts and gestures, which can be less precise than stylus-based input due to the larger area of contact of a finger on the touch screen. In some embodiments, the device translates the rough finger-based input into a precise pointer/cursor position or command for performing the actions desired by the user.

In some embodiments, in addition to the touch screen, device 100 optionally includes a touchpad (not shown) for activating or deactivating particular functions. In some embodiments, the touchpad is a touch-sensitive area of the device that, unlike the touch screen, does not display visual output. The touchpad is, optionally, a touch-sensitive surface that is separate from touch screen 112 or an extension of the touch-sensitive surface formed by the touch screen.

Device 100 also includes power system 162 for powering the various components. Power system 162 optionally includes a power management system, one or more power sources (e.g., battery, alternating current (AC)), a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator (e.g., a light-emitting diode (LED)) and any other components associated with the generation, management and distribution of power in portable devices.

Device 100 optionally also includes one or more optical sensors 164. FIG. 1A shows an optical sensor coupled to optical sensor controller 158 in I/O subsystem 106. Optical sensor 164 optionally includes charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) phototransistors. Optical sensor 164 receives light from the environment, projected through one or more lenses, and converts the light to data representing an image. In conjunction with imaging module 143 (also called a camera module), optical sensor 164 optionally captures still images or video. In some embodiments, an optical sensor is located on the back of device 100, opposite touch screen display 112 on the front of the device so that the touch screen display is enabled for use as a viewfinder for still and/or video image acquisition. In some embodiments, an optical sensor is located on the front of the device so that the user's image is, optionally, obtained for video conferencing while the user views the other video conference participants on the touch screen display. In some embodiments, the position of optical sensor 164 can be changed by the user (e.g., by rotating the lens and the sensor in the device housing) so that a single optical sensor 164 is used along with the touch screen display for both video conferencing and still and/or video image acquisition.

Device 100 optionally also includes one or more contact intensity sensors 165. FIG. 1A shows a contact intensity sensor coupled to intensity sensor controller 159 in I/O subsystem 106. Contact intensity sensor 165 optionally includes one or more piezoresistive strain gauges, capacitive force sensors, electric force sensors, piezoelectric force sensors, optical force sensors, capacitive touch-sensitive surfaces, or other intensity sensors (e.g., sensors used to measure the force (or pressure) of a contact on a touch-sensitive surface). Contact intensity sensor 165 receives contact intensity information (e.g., pressure information or a proxy for pressure information) from the environment. In some embodiments, at least one contact intensity sensor is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system 112). In some embodiments, at least one contact intensity sensor is located on the back of device 100, opposite touch screen display 112, which is located on the front of device 100.

Device 100 optionally also includes one or more proximity sensors 166. FIG. 1A shows proximity sensor 166 coupled to peripherals interface 118. Alternately, proximity sensor 166 is, optionally, coupled to input controller 160 in I/O subsystem 106. Proximity sensor 166 optionally performs as described in U.S. patent application Ser. No. 11/241,839, “Proximity Detector In Handheld Device”; Ser. No. 11/240,788, “Proximity Detector In Handheld Device”; Ser. No. 11/620,702, “Using Ambient Light Sensor To Augment Proximity Sensor Output”; Ser. No. 11/586,862, “Automated Response To And Sensing Of User Activity In Portable Devices”; and Ser. No. 11/638,251, “Methods And Systems For Automatic Configuration Of Peripherals,” which are hereby incorporated by reference in their entirety. In some embodiments, the proximity sensor turns off and disables touch screen 112 when the multifunction device is placed near the user's ear (e.g., when the user is making a phone call).

Device 100 optionally also includes one or more tactile output generators 167. FIG. 1A shows a tactile output generator coupled to haptic feedback controller 161 in I/O subsystem 106. Tactile output generator 167 optionally includes one or more electroacoustic devices such as speakers or other audio components and/or electromechanical devices that convert energy into linear motion such as a motor, solenoid, electroactive polymer, piezoelectric actuator, electrostatic actuator, or other tactile output generating component (e.g., a component that converts electrical signals into tactile outputs on the device). Contact intensity sensor 165 receives tactile feedback generation instructions from haptic feedback module 133 and generates tactile outputs on device 100 that are capable of being sensed by a user of device 100. In some embodiments, at least one tactile output generator is collocated with, or proximate to, a touch-sensitive surface (e.g., touch-sensitive display system 112) and, optionally, generates a tactile output by moving the touch-sensitive surface vertically (e.g., in/out of a surface of device 100) or laterally (e.g., back and forth in the same plane as a surface of device 100). In some embodiments, at least one tactile output generator sensor is located on the back of device 100, opposite touch screen display 112, which is located on the front of device 100.

Device 100 optionally also includes one or more accelerometers 168. FIG. 1A shows accelerometer 168 coupled to peripherals interface 118. Alternately, accelerometer 168 is, optionally, coupled to an input controller 160 in I/O subsystem 106. Accelerometer 168 optionally performs as described in U.S. Patent Publication No. 20050190059, “Acceleration-based Theft Detection System for Portable Electronic Devices,” and U.S. Patent Publication No. 20060017692, “Methods And Apparatuses For Operating A Portable Device Based On An Accelerometer,” both of which are incorporated by reference herein in their entirety. In some embodiments, information is displayed on the touch screen display in a portrait view or a landscape view based on an analysis of data received from the one or more accelerometers. Device 100 optionally includes, in addition to accelerometer(s) 168, a magnetometer (not shown and a GPS (or GLONASS or other global navigation system) receiver (not shown) for obtaining information concerning the location and orientation (e.g., portrait or landscape) of device 100.

In some embodiments, the software components stored in memory 102 include operating system 126, communication module (or set of instructions) 128, contact/motion module (or set of instructions) 130, graphics module (or set of instructions) 132, text input module (or set of instructions) 134, Global Positioning System (GPS) module (or set of instructions) 135, and applications (or sets of instructions) 136. Furthermore, in some embodiments, memory 102 (FIG. 1A) or 370 (FIG. 3) stores device/global internal state 157, as shown in FIGS. 1A and 3. Device/global internal state 157 includes one or more of: active application state, indicating which applications, if any, are currently active; display state, indicating what applications, views or other information occupy various regions of touch screen display 112; sensor state, including information obtained from the device's various sensors and input control devices 116; and location information concerning the device's location and/or attitude.

Operating system 126 (e.g., Darwin, RTXC, LINUX, UNIX, OS X, iOS, WINDOWS, or an embedded operating system such as VxWorks) includes various software components and/or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.) and facilitates communication between various hardware and software components.

Communication module 128 facilitates communication with other devices over one or more external ports 124 and also includes various software components for handling data received by RF circuitry 108 and/or external port 124. External port 124 (e.g., Universal Serial Bus (USB), FIREWIRE, etc.) is adapted for coupling directly to other devices or indirectly over a network (e.g., the Internet, wireless LAN, etc.). In some embodiments, the external port is a multi-pin (e.g., 30-pin) connector that is the same as, or similar to and/or compatible with, the 30-pin connector used on iPod® (trademark of Apple Inc.) devices.

Contact/motion module 130 optionally detects contact with touch screen 112 (in conjunction with display controller 156) and other touch-sensitive devices (e.g., a touchpad or physical click wheel). Contact/motion module 130 includes various software components for performing various operations related to detection of contact, such as determining if contact has occurred (e.g., detecting a finger-down event), determining an intensity of the contact (e.g., the force or pressure of the contact or a substitute for the force or pressure of the contact), determining if there is movement of the contact and tracking the movement across the touch-sensitive surface (e.g., detecting one or more finger-dragging events), and determining if the contact has ceased (e.g., detecting a finger-up event or a break in contact). Contact/motion module 130 receives contact data from the touch-sensitive surface. Determining movement of the point of contact, which is represented by a series of contact data, optionally includes determining speed (magnitude), velocity (magnitude and direction), and/or an acceleration (a change in magnitude and/or direction) of the point of contact. These operations are, optionally, applied to single contacts (e.g., one finger contacts) or to multiple simultaneous contacts (e.g., “multitouch”/multiple finger contacts). In some embodiments, contact/motion module 130 and display controller 156 detect contact on a touchpad.

In some embodiments, contact/motion module 130 uses a set of one or more intensity thresholds to determine whether an operation has been performed by a user (e.g., to determine whether a user has “clicked” on an icon). In some embodiments, at least a subset of the intensity thresholds are determined in accordance with software parameters (e.g., the intensity thresholds are not determined by the activation thresholds of particular physical actuators and can be adjusted without changing the physical hardware of device 100). For example, a mouse “click” threshold of a trackpad or touch screen display can be set to any of a large range of predefined threshold values without changing the trackpad or touch screen display hardware. Additionally, in some implementations, a user of the device is provided with software settings for adjusting one or more of the set of intensity thresholds (e.g., by adjusting individual intensity thresholds and/or by adjusting a plurality of intensity thresholds at once with a system-level click “intensity” parameter).

Contact/motion module 130 optionally detects a gesture input by a user. Different gestures on the touch-sensitive surface have different contact patterns (e.g., different motions, timings, and/or intensities of detected contacts). Thus, a gesture is, optionally, detected by detecting a particular contact pattern. For example, detecting a finger tap gesture includes detecting a finger-down event followed by detecting a finger-up (liftoff) event at the same position (or substantially the same position) as the finger-down event (e.g., at the position of an icon). As another example, detecting a finger swipe gesture on the touch-sensitive surface includes detecting a finger-down event followed by detecting one or more finger-dragging events, and subsequently followed by detecting a finger-up (liftoff) event.

Graphics module 132 includes various known software components for rendering and displaying graphics on touch screen 112 or other display, including components for changing the visual impact (e.g., brightness, transparency, saturation, contrast, or other visual property) of graphics that are displayed. As used herein, the term “graphics” includes any object that can be displayed to a user, including, without limitation, text, web pages, icons (such as user-interface objects including soft keys), digital images, videos, animations, and the like.

In some embodiments, graphics module 132 stores data representing graphics to be used. Each graphic is, optionally, assigned a corresponding code. Graphics module 132 receives, from applications etc., one or more codes specifying graphics to be displayed along with, if necessary, coordinate data and other graphic property data, and then generates screen image data to output to display controller 156.

Haptic feedback module 133 includes various software components for generating instructions used by tactile output generator(s) 167 to produce tactile outputs at one or more locations on device 100 in response to user interactions with device 100.

Text input module 134, which is, optionally, a component of graphics module 132, provides soft keyboards for entering text in various applications (e.g., contacts 137, e-mail 140, IM 141, browser 147, and any other application that needs text input).

GPS module 135 determines the location of the device and provides this information for use in various applications (e.g., to telephone 138 for use in location-based dialing; to camera. 143 as picture/video metadata; and to applications that provide location-based services such as weather widgets, local yellow page widgets, and map/navigation widgets).

Applications 136 optionally include the following modules (or sets of instructions), or a subset or superset thereof:

-   -   Contacts module 137 (sometimes called an address book or contact         list);     -   Telephone module 138;     -   Video conference module 139;     -   E-mail client module 140;     -   Instant messaging (IM) module 141;     -   Workout support module 142;     -   Camera module 143 for still and/or video images;     -   Image management module 144;     -   Video player module;     -   Music player module;     -   Browser module 147;     -   Calendar module 148;     -   Widget modules 149, which optionally include one or more of:         weather widget 149-1, stocks widget 149-2, calculator widget         149-3, alarm clock widget 149-4, dictionary widget 149-5, and         other widgets obtained by the user, as well as user-created         widgets 149-6;     -   Widget creator module 150 for making user-created widgets 149-6;     -   Search module 151;     -   Video and music player module 152, which merges video player         module and music player module;     -   Notes module 153;     -   Map module 154; and/or     -   Online video module 155.

Examples of other applications 136 that are, optionally, stored in memory 102 include other word processing applications, other image editing applications, drawing applications, presentation applications, JAVA-enabled applications, encryption, digital rights management, voice recognition, and voice replication.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, contacts module 137 are, optionally, used to manage an address book or contact list (e.g., stored in application internal state 192 of contacts module 137 in memory 102 or memory 370), including: adding name(s) to the address book; deleting name(s) from the address book; associating telephone number(s), e-mail address(es), physical address(es) or other information with a name; associating an image with a name; categorizing and sorting names; providing telephone numbers or e-mail addresses to initiate and/or facilitate communications by telephone 138, video conference module 139, e-mail 140, or IM 141; and so forth.

In conjunction with RF circuitry 108, audio circuitry 110, speaker 111, microphone 113, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, telephone module 138 are optionally, used to enter a sequence of characters corresponding to a telephone number, access one or more telephone numbers in contacts module 137, modify a telephone number that has been entered, dial a respective telephone number, conduct a conversation, and disconnect or hang up when the conversation is completed. As noted above, the wireless communication optionally uses any of a plurality of communications standards, protocols, and technologies.

In conjunction with RF circuitry 108, audio circuitry 110, speaker 111, microphone 113, touch screen 112, display controller 156, optical sensor 164, optical sensor controller 158, contact/motion module 130, graphics module 132, text input module 134, contacts module 137, and telephone module 138, video conference module 139 includes executable instructions to initiate, conduct, and terminate a video conference between a user and one or more other participants in accordance with user instructions.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, e-mail client module 140 includes executable instructions to create, send, receive, and manage e-mail in response to user instructions. In conjunction with image management module 144, e-mail client module 140 makes it very easy to create and send e-mails with still or video images taken with camera module 143.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, the instant messaging module 141 includes executable instructions to enter a sequence of characters corresponding to an instant message, to modify previously entered characters, to transmit a respective instant message (for example, using a Short Message Service (SMS) or Multimedia. Message Service (MMS) protocol for telephony-based instant messages or using XMPP, SIMPLE, or IMPS for Internet-based instant messages), to receive instant messages, and to view received instant messages. In some embodiments, transmitted and/or received instant messages optionally include graphics, photos, audio files, video files and/or other attachments as are supported in an MMS and/or an Enhanced Messaging Service (EMS). As used herein, “instant messaging” refers to both telephony-based messages (e.g., messages sent using SMS or MMS) and Internet-based messages (e.g., messages sent using XMPP, SIMPLE, or IMPS).

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, GPS module 135, map module 154, and music player module, workout support module 142 includes executable instructions to create workouts (e.g., with time, distance, and/or calorie burning goals); communicate with workout sensors (sports devices); receive workout sensor data; calibrate sensors used to monitor a workout; select and play music for a workout; and display, store, and transmit workout data.

In conjunction with touch screen 112, display controller 156, optical sensor(s) 164, optical sensor controller 158, contact/motion module 130, graphics module 132, and image management module 144, camera module 143 includes executable instructions to capture still images or video (including a video stream) and store them into memory 102, modify characteristics of a still image or video, or delete a still image or video from memory 102.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, and camera module 143, image management module 144 includes executable instructions to arrange, modify (e.g., edit), or otherwise manipulate, label, delete, present (e.g., in a digital slide show or album), and store still and/or video images.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, browser module 147 includes executable instructions to browse the Internet in accordance with user instructions, including searching, linking to, receiving, and displaying web pages or portions thereof, as well as attachments and other files linked to web pages.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, e-mail client module 140, and browser module 147, calendar module 148 includes executable instructions to create, display, modify, and store calendars and data associated with calendars e.g., calendar entries, to-do lists, etc. accordance with user instructions.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, and browser module 147, widget modules 149 are mini-applications that are, optionally, downloaded and used by a user (e.g., weather widget 149-1, stocks widget 149-2, calculator widget 149-3, alarm clock widget 149-4, and dictionary widget 149-5) or created by the user (e.g., user-created widget 149-6). In some embodiments, a widget includes an HTML (Hypertext Markup Language) file, a CSS (Cascading Style Sheets) file, and a JavaScript file. In some embodiments, a widget includes an XML (Extensible Markup Language) file and a JavaScript file (e.g., Yahoo! Widgets).

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, and browser module 147, the widget creator module 150 are, optionally, used by a user to create widgets (e.g., turning a user-specified portion of a web page into a widget).

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, search module 151 includes executable instructions to search for text, music, sound, image, video, and/or other files in memory 102 that match one or more search criteria (e.g., one or more user-specified search terms) in accordance with user instructions.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, audio circuitry 110, speaker 111, RF circuitry 108, and browser module 147, video and music player module 152 includes executable instructions that allow the user to download and play back recorded music and other sound files stored in one or more file formats, such as MP3 or AAC files, and executable instructions to display, present, or otherwise play back videos (e.g., on touch screen 112 or on an external, connected display via external port 124). In some embodiments, device 100 optionally includes the functionality of an MP3 player, such as an iPod (trademark of Apple Inc.).

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, and text input module 134, notes module 153 includes executable instructions to create and manage notes, to-do lists, and the like in accordance with user instructions.

In conjunction with RF circuitry 108, touch screen 112, display controller 156, contact/motion module 130, graphics module 132, text input module 134, GPS module 135, and browser module 147, map module 154 are, optionally, used to receive, display, modify, and store maps and data associated with maps (e.g., driving directions, data on stores and other points of interest at or near a particular location, and other location-based data) in accordance with user instructions.

In conjunction with touch screen 112, display controller 156, contact/motion module 130, graphics module 132, audio circuitry 110, speaker 111, RF circuitry 108, text input module 134, e-mail client module 140, and browser module 147, online video module 155 includes instructions that allow the user to access, browse, receive (e.g., by streaming and/or download), play back (e.g., on the touch screen or on an external, connected display via external port 124), send an e-mail with a link to a particular online video, and otherwise manage online videos in one or more file formats, such as H.264. In some embodiments, instant messaging module 141, rather than e-mail client module 140, is used to send a link to a particular online video. Additional description of the online video application can be found in U.S. Provisional Patent Application No. 60/936,562, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Jun. 20, 2007, and U.S. patent application Ser. No. 11/968,067, “Portable Multifunction Device, Method, and Graphical User Interface for Playing Online Videos,” filed Dec. 31, 2007, the contents of which are hereby incorporated by reference in their entirety.

Each of the above-identified modules and applications corresponds to a set of executable instructions for performing one or more functions described above and the methods described in this application (e.g., the computer-implemented methods and other information processing methods described herein). These modules (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules are, optionally, combined or otherwise rearranged in various embodiments. For example, video player module is, optionally, combined with music player module into a single module (e.g., video and music player module 152, FIG. 1A). In some embodiments, memory 102 optionally stores a subset of the modules and data structures identified above. Furthermore, memory 102 optionally stores additional modules and data structures not described above.

In some embodiments, device 100 is a device where operation of a predefined set of functions on the device is performed exclusively through a touch screen and/or a touchpad. By using a touch screen and/or a touchpad as the primary input control device for operation of device 100, the number of physical input control devices (such as push buttons, dials, and the like) on device 100 is, optionally, reduced.

The predefined set of functions that are performed exclusively through a touch screen and/or a touchpad optionally include navigation between user interfaces. In some embodiments, the touchpad, when touched by the user, navigates device 100 to a main, home, or root menu from any user interface that is displayed on device 100. In such embodiments, a “menu button” is implemented using a touchpad. In some other embodiments, the menu button is a physical push button or other physical input control device instead of a touchpad.

FIG. 1B is a block diagram illustrating exemplary components for event handling in accordance with some embodiments. In some embodiments, memory 102 (FIG. 1A) or 370 (FIG. 3) includes event sorter 170 (e.g., in operating system 126) and a respective application 136-4 (e.g., any of the aforementioned applications 137-151, 155, 380-390).

Event sorter 170 receives event information and determines the application 136-1 and application view 191 of application 136-1 to which to deliver the event information. Event sorter 170 includes event monitor 171 and event dispatcher module 174. In some embodiments, application 136-1 includes application internal state 192, which indicates the current application view(s) displayed on touch-sensitive display 112 when the application is active or executing. In some embodiments, device/global internal state 157 is used by event sorter 170 to determine which application(s) is (are) currently active, and application internal state 192 is used by event sorter 170 to determine application views 191 to which to deliver event information.

In some embodiments, application internal state 192 includes additional information, such as one or more of: resume information to be used when application 136-1 resumes execution, user interface state information that indicates information being displayed or that is ready for display by application 136-1, a state queue for enabling the user to go back to a prior state or view of application 136-1, and a redo/undo queue of previous actions taken by the user.

Event monitor 171 receives event information from peripherals interface 118. Event information includes information about a sub-event (e.g., a user touch on touch-sensitive display 112, as part of a multi-touch gesture). Peripherals interface 118 transmits information it receives from I/O subsystem 106 or a sensor, such as proximity sensor 166, accelerometer(s) 168, and/or microphone 113 (through audio circuitry 110). Information that peripherals interface 118 receives from I/O subsystem 106 includes information from touch-sensitive display 112 or a touch-sensitive surface.

In some embodiments, event monitor 171 sends requests to the peripherals interface 118 at predetermined intervals. In response, peripherals interface 118 transmits event information. In other embodiments, peripherals interface 118 transmits event information only when there is a significant event (e.g., receiving an input above a predetermined noise threshold and/or for more than a predetermined duration).

In some embodiments, event sorter 170 also includes a hit view determination module 172 and/or an active event recognizer determination module 173.

Hit view determination module 172 provides software procedures for determining where a sub-event has taken place within one or more views when touch-sensitive display 112 displays more than one view. Views are made up of controls and other elements that a user can see on the display.

Another aspect of the user interface associated with an application is a set of views, sometimes herein called application views or user interface windows, in which information is displayed and touch-based gestures occur. The application views (of a respective application) in which a touch is detected optionally correspond to programmatic levels within a programmatic or view hierarchy of the application. For example, the lowest level view in which a touch is detected is, optionally, called the hit view, and the set of events that are recognized as proper inputs are, optionally, determined based, at least in part, on the hit view of the initial touch that begins a touch-based gesture.

Hit view determination module 172 receives information related to sub-events of a touch-based gesture. When an application has multiple views organized in a hierarchy, hit view determination module 172 identifies a hit view as the lowest view in the hierarchy which should handle the sub-event. In most circumstances, the hit view is the lowest level view in which an initiating sub-event occurs (e.g., the first sub-event in the sequence of sub-events that form an event or potential event). Once the hit view is identified by the hit view determination module 172, the hit view typically receives all sub-events related to the same touch or input source for which it was identified as the hit view.

Active event recognizer determination module 173 determines which view or views within a view hierarchy should receive a particular sequence of sub-events. In some embodiments, active event recognizer determination module 173 determines that only the hit view should receive a particular sequence of sub-events. In other embodiments, active event recognizer determination module 173 determines that all views that include the physical location of a sub-event are actively involved views, and therefore determines that all actively involved views should receive a particular sequence of sub-events. In other embodiments, even if touch sub-events were entirely confined to the area associated with one particular view, views higher in the hierarchy would still remain as actively involved views.

Event dispatcher module 174 dispatches the event information to an event recognizer (e.g., event recognizer 180). In embodiments including active event recognizer determination module 173, event dispatcher module 174 delivers the event information to an event recognizer determined by active event recognizer determination module 173. In some embodiments, event dispatcher module 174 stores in an event queue the event information, which is retrieved by a respective event receiver 182.

In some embodiments, operating system 126 includes event sorter 170. Alternatively, application 136-1 includes event sorter 170. In yet other embodiments, event sorter 170 is a stand-alone module, or a part of another module stored in memory 102, such as contact/motion module 130.

In some embodiments, application 136-1 includes a plurality of event handlers 190 and one or more application views 191, each of which includes instructions for handling touch events that occur within a respective view of the application's user interface. Each application view 191 of the application 136-1 includes one or more event recognizers 180. Typically, a respective application view 191 includes a plurality of event recognizers 180. In other embodiments, one or more of event recognizers 180 are part of a separate module, such as a user interface kit (not shown) or a higher level object from which application 136-1 inherits methods and other properties. In some embodiments, a respective event handler 190 includes one or more of: data updater 176, object updater 177, GUI updater 178, and/or event data 179 received from event sorter 170. Event handler 190 optionally utilizes or calls data updater 176, object updater 177, or GUI updater 178 to update the application internal state 192. Alternatively, one or more of the application views 191 include one or more respective event handlers 190. Also, in some embodiments, one or more of data updater 176, object updater 177, and GUI updater 178 are included in a respective application view 191.

A respective event recognizer 180 receives event information (e.g., event data 179) from event sorter 170 and identifies an event from the event information. Event recognizer 180 includes event receiver 182 and event comparator 184. In some embodiments, event recognizer 180 also includes at least a subset of: metadata 183, and event delivery instructions 188 (which optionally include sub-event delivery instructions).

Event receiver 182 receives event information from event sorter 170. The event information includes information about a sub-event, for example, a touch or a touch movement. Depending on the sub-event, the event information also includes additional information, such as location of the sub-event. When the sub-event concerns motion of a touch, the event information optionally also includes speed and direction of the sub-event. In some embodiments, events include rotation of the device from one orientation to another (e.g., from a portrait orientation to a landscape orientation, or vice versa), and the event information includes corresponding information about the current orientation (also called device attitude) of the device.

Event comparator 184 compares the event information to predefined event or sub-event definitions and, based on the comparison, determines an event or sub-event, or determines or updates the state of an event or sub-event. In some embodiments, event comparator 184 includes event definitions 186. Event definitions 186 contain definitions of events (e.g., predefined sequences of sub-events), for example, event 1 (187-1), event 2 (187-2), and others. In some embodiments, sub-events in an event (187) include, for example, touch begin, touch end, touch movement, touch cancellation, and multiple touching. In one example, the definition for event 1 (187-1) is a double tap on a displayed object. The double tap, for example, comprises a first touch (touch begin) on the displayed object for a predetermined phase, a first liftoff (touch end) for a predetermined phase, a second touch (touch begin) on the displayed object for a predetermined phase, and a second liftoff (touch end) for a predetermined phase. In another example, the definition for event 2 (187-2) is a dragging on a displayed object. The dragging, for example, comprises a touch (or contact) on the displayed object for a predetermined phase, a movement of the touch across touch-sensitive display 112, and liftoff of the touch (touch end). In some embodiments, the event also includes information for one or more associated event handlers 190.

In some embodiments, event definition 187 includes a definition of an event for a respective user-interface object. In some embodiments, event comparator 184 performs a hit test to determine which user-interface object is associated with a sub-event. For example, in an application view in which three user-interface objects are displayed on touch-sensitive display 112, when a touch is detected on touch-sensitive display 112, event comparator 184 performs a hit test to determine which of the three user-interface objects is associated with the touch (sub-event). If each displayed object is associated with a respective event handler 190, the event comparator uses the result of the hit test to determine which event handler 190 should be activated. For example, event comparator 184 selects an event handler associated with the sub-event and the object triggering the hit test.

In some embodiments, the definition for a respective event (187) also includes delayed actions that delay delivery of the event information until after it has been determined whether the sequence of sub-events does or does not correspond to the event recognizer's event type.

When a respective event recognizer 180 determines that the series of sub-events do not match any of the events in event definitions 186, the respective event recognizer 180 enters an event impossible, event failed, or event ended state, after which it disregards subsequent sub-events of the touch-based gesture. In this situation, other event recognizers, if any, that remain active for the hit view continue to track and process sub-events of an ongoing touch-based gesture.

In some embodiments, a respective event recognizer 180 includes metadata 183 with configurable properties, flags, and/or lists that indicate how the event delivery system should perform sub-event delivery to actively involved event recognizers. In some embodiments, metadata 183 includes configurable properties, flags, and/or lists that indicate how event recognizers interact, or are enabled to interact, with one another. In some embodiments, metadata 183 includes configurable properties, flags, and/or lists that indicate whether sub-events are delivered to varying levels in the view or programmatic hierarchy.

In some embodiments, a respective event recognizer 180 activates event handler 190 associated with an event when one or more particular sub-events of an event are recognized. In some embodiments, a respective event recognizer 180 delivers event information associated with the event to event handler 190. Activating an event handler 190 is distinct from sending (and deferred sending) sub-events to a respective hit view. In some embodiments, event recognizer 180 throws a flag associated with the recognized event, and event handler 190 associated with the flag catches the flag and performs a predefined process.

In some embodiments, event delivery instructions 188 include sub-event delivery instructions that deliver event information about a sub-event without activating an event handler. Instead, the sub-event delivery instructions deliver event information to event handlers associated with the series of sub-events or to actively involved views. Event handlers associated with the series of sub-events or with actively involved views receive the event information and perform a predetermined process.

In some embodiments, data updater 176 creates and updates data used in application 136-1. For example, data updater 176 updates the telephone number used in contacts module 137, or stores a video file used in video player module. In some embodiments, object updater 177 creates and updates objects used in application 136-1. For example, object updater 177 creates a new user-interface object or updates the position of a user-interface object. GUI updater 178 updates the GUI. For example, GUI updater 178 prepares display information and sends it to graphics module 132 for display on a touch-sensitive display.

In some embodiments, event handler(s) 190 includes or has access to data updater 176, object updater 177, and GUI updater 178. In some embodiments, data updater 176, object updater 177, and GUI updater 178 are included in a single module of a respective application 136-1 or application view 191. In other embodiments, they are included in two or more software modules.

It shall be understood that the foregoing discussion regarding event handling of user touches on touch-sensitive displays also applies to other forms of user inputs to operate multifunction devices 100 with input devices, not all of which are initiated on touch screens. For example, mouse movement and mouse button presses, optionally coordinated with single or multiple keyboard presses or holds; contact movements such as taps, drags, scrolls, etc. on touchpads; pen stylus inputs; movement of the device; oral instructions; detected eye movements; biometric inputs; and/or any combination thereof are optionally utilized as inputs corresponding to sub-events which define an event to be recognized.

FIG. 2 illustrates a portable multifunction device 100 having a touch screen 112 in accordance with some embodiments. The touch screen optionally displays one or more graphics within user interface (UI) 200. In this embodiment, as well as others described below, a user is enabled to select one or more of the graphics by making a gesture on the graphics, for example, with one or more fingers 202 (not drawn to scale in the figure) or one or more styluses 203 (not drawn to scale in the figure). In some embodiments, selection of one or more graphics occurs when the user breaks contact with the one or more graphics. In some embodiments, the gesture optionally includes one or more taps, one or more swipes (from left to right, right to left, upward and/or downward), and/or a rolling of a finger (from right to left, left to right, upward and/or downward) that has made contact with device 100. In some implementations or circumstances, inadvertent contact with a graphic does not select the graphic. For example, a swipe gesture that sweeps over an application icon optionally does not select the corresponding application when the gesture corresponding to selection is a tap.

Device 100 optionally also include one or more physical buttons, such as “home” or menu button 204. As described previously, menu button 204 is, optionally, used to navigate to any application 136 in a set of applications that are, optionally, executed on device 100. Alternatively, in some embodiments, the menu button is implemented as a soft key in a GUI displayed on touch screen 112.

In some embodiments, device 100 includes touch screen 112, menu button 204, push button 206 for powering the device on/off and locking the device, volume adjustment button(s) 208, subscriber identity module (SIM) card slot 210, headset jack 212, and docking/charging external port 124. Push button 206 is, optionally, used to turn the power on/off on the device by depressing the button and holding the button in the depressed state for a predefined time interval; to lock the device by depressing the button and releasing the button before the predefined time interval has elapsed; and/or to unlock the device or initiate an unlock process. In an alternative embodiment, device 100 also accepts verbal input for activation or deactivation of some functions through microphone 113. Device 100 also, optionally, includes one or more contact intensity sensors 165 for detecting intensity of contacts on touch screen 112 and/or one or more tactile output generators 167 for generating tactile outputs for a user of device 100.

FIG. 3 is a block diagram of an exemplary multifunction device with a display and a touch-sensitive surface in accordance with some embodiments. Device 300 need not be portable. In some embodiments, device 300 is a laptop computer, a desktop computer, a tablet computer, a multimedia player device, a navigation device, an educational device (such as a child's learning toy), a gaming system, or a control device (e.g., a home or industrial controller). Device 300 typically includes one or more processing units (CPUs) 310, one or more network or other communications interfaces 360, memory 370, and one or more communication buses 320 for interconnecting these components. Communication buses 320 optionally include circuitry (sometimes called a chipset) that interconnects and controls communications between system components. Device 300 includes input/output (I/O) interface 330 comprising display 340, which is typically a touch screen display. I/O interface 330 also optionally includes a keyboard and/or mouse (or other pointing device) 350 and touchpad 355, tactile output generator 357 for generating tactile outputs on device 300 (e.g., similar to tactile output generator(s) 167 described above with reference to FIG. 1A), sensors 359 (e.g., optical, acceleration, proximity, touch-sensitive, and/or contact intensity sensors similar to contact intensity sensor(s) 165 described above with reference to FIG. 1A). Memory 370 includes high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices; and optionally includes non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. Memory 370 optionally includes one or more storage devices remotely located from CPU(s) 310. In some embodiments, memory 370 stores programs, modules, and data structures analogous to the programs, modules, and data structures stored in memory 102 of portable multifunction device 100 (FIG. 1A), or a subset thereof. Furthermore, memory 370 optionally stores additional programs, modules, and data structures not present in memory 102 of portable multifunction device 100. For example, memory 370 of device 300 optionally stores drawing module 380, presentation module 382, word processing module 384, website creation module 386, disk authoring module 388, and/or spreadsheet module 390, while memory 102 of portable multifunction device 100 (FIG. 1A) optionally does not store these modules.

Each of the above-identified elements in FIG. 3 is, optionally, stored in one or more of the previously mentioned memory devices. Each of the above-identified modules corresponds to a set of instructions for performing a function described above. The above-identified modules or programs (e.g., sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules are, optionally, combined or otherwise rearranged in various embodiments. In some embodiments, memory 370 optionally stores a subset of the modules and data structures identified above. Furthermore, memory 370 optionally stores additional modules and data structures not described above.

Attention is now directed towards embodiments of user interfaces that are, optionally, implemented on, for example, portable multifunction device 100.

FIG. 4A illustrates an exemplary user interface for a menu of applications on portable multifunction device 100 in accordance with some embodiments. Similar user interfaces are, optionally, implemented on device 300. In some embodiments, user interface 400 includes the following elements, or a subset or superset thereof:

-   -   Signal strength indicator(s) 402 for wireless communication(s),         such as cellular and Wi-Fi signals;     -   Time 404;     -   Bluetooth indicator 405;     -   Battery status indicator 406;     -   Tray 408 with icons for frequently used applications, such as:         -   Icon 416 for telephone module 138, labeled “Phone,” which             optionally includes an indicator 414 of the number of missed             calls or voicemail messages;         -   Icon 418 for e-mail client module 140, labeled “Mail,” which             optionally includes an indicator 410 of the number of unread             e-mails;         -   icon 420 for browser module 147, labeled “Browser;” and         -   Icon 422 for video and music player module 152, also             referred to as iPod (trademark of Apple Inc.) module 152,             labeled “iPod;” and     -   Icons for other applications, such as:         -   Icon 424 for IM module 141, labeled “Messages;”         -   icon 426 for calendar module 148, labeled “Calendar;”         -   Icon 428 for image management module 144, labeled “Photos;”         -   Icon 430 for camera module 143, labeled “Camera;”         -   Icon 432 for online video module 155, labeled “Online             Video;”         -   Icon 434 for stocks widget 149-2, labeled “Stocks;”         -   Icon 436 for map module 154, labeled “Maps;”         -   Icon 438 for weather widget 149-1, labeled “Weather;”         -   Icon 440 for alarm clock widget 149-4, labeled “Clock;”         -   Icon 442 for workout support module 142, labeled “Workout             Support;”         -   Icon 444 for notes module 153, labeled “Notes;” and         -   icon 446 for a settings application or module, labeled             “Settings,” which provides access to settings for device 100             and its various applications 136.

It should be noted that the icon labels illustrated in FIG. 4A are merely exemplary. For example, icon 422 for video and music player module 152 is labeled “Music” or “Music Player.” Other labels are, optionally, used for various application icons. In some embodiments, a label for a respective application icon includes a name of an application corresponding to the respective application icon. In some embodiments, a label for a particular application icon is distinct from a name of an application corresponding to the particular application icon.

FIG. 4B illustrates an exemplary user interface on a device (e.g., device 300, FIG. 3) with a touch-sensitive surface 451 (e.g., a tablet or touchpad 355, FIG. 3) that is separate from the display 450 (e.g., touch screen display 112). Device 300 also, optionally, includes one or more contact intensity sensors (e.g., one or more of sensors 359) for detecting intensity of contacts on touch-sensitive surface 451 and/or one or more tactile output generators 357 for generating tactile outputs for a user of device 300.

Although some of the examples that follow will be given with reference to inputs on touch screen display 112 (where the touch-sensitive surface and the display are combined), in some embodiments, the device detects inputs on a touch-sensitive surface that is separate from the display, as shown in FIG. 4B. In some embodiments, the touch-sensitive surface (e.g., 451 in FIG. 4B) has a primary axis (e.g., 452 in FIG. 4B) that corresponds to a primary axis (e.g., 453 in FIG. 4B) on the display (e.g., 450). In accordance with these embodiments, the device detects contacts (e.g., 460 and 462 in FIG. 4B) with the touch-sensitive surface 451 at locations that correspond to respective locations on the display (e.g., in FIG. 4B, 460 corresponds to 468 and 462 corresponds to 470). In this way, user inputs (e.g., contacts 460 and 462, and movements thereof) detected by the device on the touch-sensitive surface (e.g., 451 in FIG. 4B) are used by the device to manipulate the user interface on the display (e.g., 450 in FIG. 4B) of the multifunction device when the touch-sensitive surface is separate from the display. It should be understood that similar methods are, optionally, used for other user interfaces described herein.

Additionally, while the following examples are given primarily with reference to finger inputs (e.g., finger contacts, finger tap gestures, finger swipe gestures), it should be understood that, in some embodiments, one or more of the finger inputs are replaced with input from another input device (e.g., a mouse-based input or stylus input). For example, a swipe gesture is, optionally, replaced with a mouse click (e.g., instead of a contact) followed by movement of the cursor along the path of the swipe (e.g., instead of movement of the contact). As another example, a tap gesture is, optionally, replaced with a mouse click while the cursor is located over the location of the tap gesture (e.g., instead of detection of the contact followed by ceasing to detect the contact). Similarly, when multiple user inputs are simultaneously detected, it should be understood that multiple computer mice are, optionally, used simultaneously, or a mouse and finger contacts are, optionally, used simultaneously.

FIG. 5A illustrates exemplary personal electronic device 500. Device 500 includes body 502. In some embodiments, device 500 can include some or all of the features described with respect to devices 100 and 300 (e.g., FIGS. 1A-4B). In some embodiments, device 500 has touch-sensitive display screen 504, hereafter touch screen 504. Alternatively, or in addition to touch screen 504, device 500 has a display and a touch-sensitive surface. As with devices 100 and 300, in some embodiments, touch screen 504 (or the touch-sensitive surface) optionally includes one or more intensity sensors for detecting intensity of contacts (e.g., touches) being applied. The one or more intensity sensors of touch screen 504 (or the touch-sensitive surface) can provide output data that represents the intensity of touches. The user interface of device 500 can respond to touches based on their intensity, meaning that touches of different intensities can invoke different user interface operations on device 500.

Exemplary techniques for detecting and processing touch intensity are found, for example, in related applications: International Patent Application Serial No. PCT/US2013/040061, titled “Device, Method, and Graphical User Interface for Displaying User Interface Objects Corresponding to an Application,” filed May 8, 2013, published as WIPO Publication No. WO/2013/169849, and International Patent Application Serial No. PCT/US2013/069483, titled “Device, Method, and Graphical User Interface for Transitioning Between Touch Input to Display Output Relationships,” filed Nov. 11, 2013, published as WIPO Publication No. WO/2014/105276, each of which is hereby incorporated by reference in their entirety.

In some embodiments, device 500 has one or more input mechanisms 506 and 508. Input mechanisms 506 and 508, if included, can be physical. Examples of physical input mechanisms include push buttons and rotatable mechanisms. In some embodiments, device 500 has one or more attachment mechanisms. Such attachment mechanisms, if included, can permit attachment of device 500 with, for example, hats, eyewear, earrings, necklaces, shirts, jackets, bracelets, watch straps, chains, trousers, belts, shoes, purses, backpacks, and so forth. These attachment mechanisms permit device 500 to be worn by a user.

FIG. 5B depicts exemplary personal electronic device 500. In some embodiments, device 500 can include some or all of the components described with respect to FIGS. 1A, 1B, and 3. Device 500 has bus 512 that operatively couples I/O section 514 with one or more computer processors 516 and memory 518. I/O section 514 can be connected to display 504, which can have touch-sensitive component 522 and, optionally, intensity sensor 524 (e.g., contact intensity sensor). In addition, I/O section 514 can be connected with communication unit 530 for receiving application and operating system data, using Wi-Fi, Bluetooth, near field communication (NFC), cellular, and/or other wireless communication techniques. Device 500 can include input mechanisms 506 and/or 508. Input mechanism 506 is, optionally, a rotatable input device or a depressible and rotatable input device, for example. Input mechanism 508 is, optionally, a button, in some examples.

Input mechanism 508 is, optionally, a microphone, in some examples. Personal electronic device 500 optionally includes various sensors, such as GPS sensor 532, accelerometer 534, directional sensor 540 (e.g., compass), gyroscope 536, motion sensor 538, and/or a combination thereof, all of which can be operatively connected to I/O section 514.

Memory 518 of personal electronic device 500 can include one or more non-transitory computer-readable storage mediums, for storing computer-executable instructions, which, when executed by one or more computer processors 516, for example, can cause the computer processors to perform the techniques described below, including processes 800 and 900 (FIGS. 8 and 9). Personal electronic device 500 is not limited to the components and configuration of FIG. 5B, but can include other or additional components in multiple configurations.

As used here, the term “affordance” refers to a user-interactive graphical user interface object that is, optionally, displayed on the display screen of devices 100, 300, and/or 500 (FIGS. 1, 3, and 5). For example, an image (e.g., icon), a button, and text (e.g., hyperlink) each optionally constitute an accordance.

As used herein, the term “focus selector” refers to an input element that indicates a current part of a user interface with which a user is interacting. In some implementations that include a cursor or other location marker, the cursor acts as a “focus selector” so that when an input (e.g., a press input) is detected on a touch-sensitive surface (e.g., touchpad 355 in FIG. 3 or touch-sensitive surface 451 in FIG. 4B) while the cursor is over a particular user interface element (e.g., a button, window, slider, or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations that include a touch screen display (e.g., touch-sensitive display system 112 in FIG. 1A or touch screen 112 in FIG. 4A) that enables direct interaction with user interface elements on the touch screen display, a detected contact on the touch screen acts as a “focus selector” so that when an input (e.g., a press input by the contact) is detected on the touch screen display at a location of a particular user interface element (e.g., a button, window, slider, or other user interface element), the particular user interface element is adjusted in accordance with the detected input. In some implementations, focus is moved from one region of a user interface to another region of the user interface without corresponding movement of a cursor or movement of a contact on a touch screen display (e.g., by using a tab key or arrow keys to move focus from one button to another button); in these implementations, the focus selector moves in accordance with movement of focus between different regions of the user interface. Without regard to the specific form taken by the focus selector, the focus selector is generally the user interface element (or contact on a touch screen display) that is controlled by the user so as to communicate the user's intended interaction with the user interface (e.g., by indicating, to the device, the element of the user interface with which the user is intending to interact). For example, the location of a focus selector (e.g., a cursor, a contact, or a selection box) over a respective button while a press input is detected on the touch-sensitive surface (e.g., a touchpad or touch screen) will indicate that the user is intending to activate the respective button (as opposed to other user interface elements shown on a display of the device).

1. Morpheme-Based Language Models

In n-gram language modeling, word inflection generally increases the size of the underlying vocabulary needed for word prediction, as each inflected form of a word (e.g., “talks”, “talked”, “talking”) can be thought of as its own word by the language model. This increase in vocabulary leads to attendant problems such as difficulties in obtaining sufficient training data and resulting language models that are larger than ideal for deployment onto portable electronic devices. For these reasons, a brute force approach to handling word inflections is, while theoretically possible, not yet practical.

Alternative methods instead look to partition words into morphemes (e.g., prefixes, stems, and/or suffixes). In general, any number of words can be broken into a respective number of morphemes, and a morpheme-based language model can be trained to operate on the word(s). This ability to operate using morpheme-based language models provides robust predictions while requiring reduced amounts of training data. As a result, morpheme-based language models, such as those described herein, are more suitable for deployment on devices having relatively limited processing and storage capability.

For the purposes of examples described herein, let W₀ ^(T)=w₀w₁ . . . w_(t−1)w_(t) denote the sequence of words relevant to a prediction of a current word w_(t). Further, in at least one example, assume that w_(t) can be decomposed into a concatenated sequence of morphemes in accordance with the following equation: w _(t) =p _(t) ⁽¹⁾ . . . p _(t) ^((J)) s _(t) f _(t) ⁽¹⁾ . . . f _(t) ^((K)) where J and K represent the zero or more prefixes and zero or more suffixes of a stem s_(t), respectively. 2. Sequential Morpheme-Based Language Model

Conventional morpheme-based language models determine a likelihood (e.g., probability) of a current word w_(t) based on a given context (e.g., word history) of the word w_(t). For example, by virtue of the standard chain rule:

P_(r)(w_(t)|W₀^(t − 1)) = P_(r)(f_(t)^((K))|W₀^(t − 1)p_(t)⁽¹⁾  …  p_(t)^((J))s_(t)f_(t)⁽¹⁾  …  f^((K − 1)))⋅ …  P_(r)(f_(t)⁽¹⁾|W₀^(t − 1)p_(t)⁽¹⁾  …  p_(t)^((J))s_(t)) ⋅ P_(r)(s_(t)|W₀^(t − 1)p_(t)⁽¹⁾  …  p_(t)^((J))) ⋅ P_(r)(p_(t)^((J))|W₀^(t − 1)p_(t)⁽¹⁾  …  p_(t)^((J − 1)))⋅ …  P_(r)(p_(t)⁽¹⁾|W₀^(t − 1)), where W₀ ^(t−1) represents the previous word context (e.g., context of word associated with time step t−1), and all other conditioning elements arise from the morphological decomposition of w_(t). Though models of this type are capable of providing relatively significant coverage while relying on a relatively small underlying vocabulary, in some examples, such models are limited by ordering constraints specified by training data. 3. Concurrent Morpheme-Based Language Model

In some examples, it may be desirable to decouple morpheme prediction such that morpheme redundancy in training data may be more effectively leveraged. Thus, examples described herein are directed to morpheme-based text prediction in which the typical limitations associated with the expansion of sequences of input tokens are mitigated and/or altogether avoided. In doing so, morpheme-based text prediction may be implemented using a relatively small amount of training data relative to previous known approaches. In at least one example, a multi-task architecture (e.g., network) is employed such that all sub-words (e.g., prefixes, stems, suffixes) for a word are predicted, at least in part, concurrently. In this manner, aspects of grammatical agreement (e.g., for prefixes and/or suffixes) may be decoupled from stem interference. While disregarding syntactic relationships between morphemes in this manner requires restructuring words after morpheme prediction, lexicon-based consistency checks may be employed to address this issue, as described in further detail below.

Under this approach, a probability of a current word w_(t) may be determined according to the following equation:

P_(r)(w_(t)|W₀^(t − 1)) = P_(r)(f_(t)^((K))|W₀^(t − 1)C_(p)C_(s)C_(f))⋅ …  P_(r)(f_(t)⁽¹⁾|W₀^(t − 1)C_(p)C_(s)C_(f)) ⋅ P_(r)(s_(t)|W₀^(t − 1)C_(p)) ⋅ P_(r)(p_(t)^((J))|W₀^(t − 1)C_(p))⋅ …  P_(r)(p_(t)⁽¹⁾|W₀^(t − 1)C_(p)), where generic categories C_(p), C_(s), and C_(f) represent correspond to the presence of one or more prefixes, a stem, and/or one or more suffixes, respectively. In this manner, the context of each prefix, stem, and suffix is based solely on the context W₀ ^(t−1). In some examples, C_(p) may indicate that no prefix exists and/or C_(f) may indicate that no suffix exists.

FIG. 6 illustrates an exemplary block diagram of text prediction system 600 in accordance with some embodiments. In some embodiments, text prediction system 600 is implemented using one or more multifunction devices, including, but not limited to, devices 100, 200, 300, and 500 (FIGS. 1A, 2, 3, and 5A). In some examples, memory 102 (FIG. 1A) or 370 (FIG. 3) includes text prediction system 600.

Generally, the text prediction system 600 operates to provide (e.g., predict) a next word given a current word and/or a context (e.g., word history) of the current word. In some examples, providing a next word in this manner includes providing one or more prefixes, stems, and/or suffixes, and selecting a concatenated subset of the prefixes, stems, and/or suffixes as the next word.

It should be recognized that text prediction system 600 need not be implemented as a separate software program, procedure, or module, and thus, various components of the text prediction system are, optionally, combined, separated, or otherwise rearranged. For instance, although the text prediction module 600 is illustrated as including a text prediction engine 605 canonical verification engine 610, and a candidate ranking engine 615, it will be appreciated that the text prediction module 600 may implement additional or fewer components in some examples.

In operation, the text prediction engine 605 receives a current word, and, based on the current word and context of the current word, provides probabilities for each potential prefix, stem, and suffix of a next word. As described in further detail below, in some examples, the text prediction engine 605 provides a representation indicating a probability for each potential prefix, a representation indicating a probability for each potential stem, and a representation indicating a probability indicating a probability for each potential suffix.

Each of the probabilities provided by the text prediction engine 605 are received by the canonical verification engine 610. Based on the received probabilities, the canonical verification engine 610 generates a plurality of candidate next words. By way of example, the canonical verification engine 610 may identify a predetermined number of morphemes (i.e., prefixes, stems, and/or suffixes) having the highest probabilities as indicated by prediction engine 605. Additionally or alternatively, the canonical verification engine 610 may identify morphemes associated with a probability exceeding a predetermined threshold.

The canonical verification engine 610 may generate candidate next words based on the identified morphemes. In some examples, the canonical verification engine 610 generates candidate next words by determining each possible combination of the identified morphemes and comparing each combination of morphemes to one or more lexicons (e.g., English lexicon, user-specific lexicon, multi-lingual lexicon). Combinations generated in this manner may include all identified morphemes or any subset thereof, and further may be concatenated in any manner provided prefixes precede stems, and stems precede suffixes. Those combinations consistent with (e.g., included in) the one or more lexicons of the canonical verification engine 610 may be provided as candidate next words. Additionally or alternatively, candidate next words can be generated according to a set of predetermined canonical rules. In this manner, the number of candidates generated may be reduced. By way of example, because the English plural marker “s” always comes last in any English word, any combination of identified morphemes in which the marker “s” would not come last may be ignored. Providing candidate next words in this manner ensures that each candidate word is a valid word or phrase.

Candidate next words provided by the canonical verification engine 610 may be received by the candidate ranking engine 615. In turn, the candidate ranking engine 615 may rank each of the candidate next words according to a determined probability. In some examples, the probability of each candidate next word is determined according to the following equation used to determine a probability of a word w_(t):

P_(r)(w_(t)|W₀^(t − 1)) = P_(r)(f_(t)^((K))|W₀^(t − 1)C_(p)C_(s)C_(f))⋅ …  P_(r)(f_(t)⁽¹⁾|W₀^(t − 1)C_(p)C_(s)C_(f)) ⋅ P_(r)(s_(t)|W₀^(t − 1)C_(p)) ⋅ P_(r)(p_(t)^((J))|W₀^(t − 1)C_(p))⋅ …  P_(r)(p_(t)⁽¹⁾|W₀^(t − 1)C_(p)),

Once each of the candidate next words have been ranked, the candidate ranking engine 615 provides the candidate next word associated with the highest probability as the determined next word. The determined next word may, for instance, be displayed on a display of an electronic device for user selection (e.g., during operation of a messaging application). The candidate ranking engine 615 further may provide one or more additional candidate next words in some examples.

FIG. 7 illustrates a text prediction network 700 in accordance with some embodiments. Generally, the text prediction network 700 may be a neural network (e.g., recurrent neural network) that may serve to predict a next word (e.g., next word of a sentence, completed version of a current partial word) in response to receipt of one or more words or partial words. The text prediction network 700 may be used to implement, at least in part, the text prediction engine 605 and further may be implemented using one or more multifunction devices including but not limited to devices 100, 200, 300, and 500 (FIGS. 1A, 2, 3, and 5A).

The text prediction network 700 includes multiple layers in some examples. The text prediction network 700 may, for instance, include an input layer 710, one or more hidden layers 750, and an output layer 760. In the illustrated example, text prediction network 700 includes a single hidden layer 750. It will be appreciated, however, that in other examples, the text prediction network 700 may include one more additional hidden layers.

Each layer of the text prediction network 700 may comprise any number of units. A layer may, for instance, comprise a single unit or may comprise multiple units. These units, which in some examples may be referred to as dimensions, neurons, or nodes (e.g., context nodes), may operate as the computational elements of the text prediction network 700. As illustrated, in some examples, the input layer 710 includes a current prefix unit 720, a current stem unit 730, and a current suffix unit 740. The hidden layer 750 includes a current context unit 755. Optionally, the current context unit 755 receives context of a previous word (or words) from a previous context unit 757. The previous context unit is included in the input layer 710 in some examples. The output layer 760 includes a next prefix unit 770, a next stem unit 780, and a next suffix unit 790. Units of the text prediction network 700 further may be interconnected using connections. Connections may be unidirectional or bidirectional, and further may be associated with a respective weight value. Each weight value specifies a strength of the corresponding connection and accordingly the relative influence of the value(s) provided via the connection. As illustrated, each of the current prefix unit 720, current stem unit 730, and current suffix unit 740 are connected to the current context unit 755, and the current context unit 755 is connected to the next prefix unit 770, next stem unit 780, and next suffix unit 790.

In operation, the input layer 710 receives a current word w_(t) of a word sequence (e.g., a sentence) and provides a current input corresponding to the current word w_(t) to the hidden layer 750 via connections interconnected between units of the input layer 710 and the hidden layer 750. Generally, the current input is a representation of the current word (e.g., vector, spatial representation).

In some examples, the current input is provided by encoding the current word. In particular, the current word w_(t) may be encoded based on one or more identified prefixes, stem, and/or suffixes of the current word w_(t). By way of example, any prefixes of the current word may be encoded in a vector p_(t) of length P, a stem of the current word may be encoded in a vector s_(t) of length S, and any suffixes of the current word may be encoded in a vector f_(t) of length F, where P, S, and F indicate a number of total token inventory for prefixes, stems, and suffixes respectively. Accordingly, the current word w_(t) can have a dimensionality of N, where N=P+S+F, and be encoded as n-of-N, where n is a relatively small integer (e.g., 0<n<6). In some examples, the current word w_(t) may not include a prefix and the vector p_(t) may indicate that the current word w_(t) does not includes a prefix. That is, the vector p_(t) may indicate that a prefix of the current word w_(t) is empty. Similarly, in some examples, the current word may not include a suffix and the vector f_(t) may indicate that the current word w_(t) does not include a suffix. That is, the vector f_(t) may indicate that a suffix of the current word w_(t) is empty.

Consider, for example, a current word “mis-redirectional,” which includes two prefixes (i.e., “mis” and “re”) encoded in a vector p_(t) of length P, a stem (i.e., direct) encoded in a vector s_(t) of length S, and two suffixes (“ion” and “al”) encoded in a vector f_(t) of length F. Each of the prefixes “mis” and “re” may be represented as elements (e.g., indices) 722 and 724 of the vector p_(t), respectively. The stem “direct” may be represented as element 732 of the vector s_(t). The suffixes “ion” and “al” may be represented as elements 742 and 744 of the vector f_(t), respectively. Consider another example current word “denounce” (not depicted), which includes a prefix (i.e., “de”) encoded in a vector p_(t) of length P and a stem (i.e., nounce) encoded in a vector s_(t) of length S. The prefix “de” would be represented as an element of the vector p_(t), and the stem “nounce” would be represented as an element of the vector s_(t). Because the word “denounce” does not have a suffix, the vector f_(t) would indicate that no suffix exists in the current word (e.g., an element of the vector f_(t) corresponding to “empty” may have a non-zero value).

Each of the current prefix unit 720, current stem unit 730, and current suffix unit 740 of the input layer 710 are connected to the current context unit 755 of the hidden layer 750 and provide the vectors p_(t), s_(t), and f_(t), to the current context unit 755, respectively. The previous context unit 757 is connected to the current context unit 755 and provides a context value h_(t−1). The context value h_(t−1) comprises the context of a previous input (e.g., previous word) at a previous time step (e.g., time step t−1) and may have a dimension of H in some examples. Based on the context received from the previous context unit 757 and vectors p_(t), s_(t), and f_(t) received from the current prefix unit 720, current stem unit 730, and current suffix unit 740, respectively, the current context unit 755 determines a current context value h_(t).

As described, in some examples, connections may be weighted. The connections between the input layer 710 and the hidden layer 750 may be weighted according to a weight matrix P. P may, for instance, be defined in accordance with the following:

$P = \begin{matrix} {X\; 1} & 0 & 0 \\ 0 & X & 0 \\ 0 & 0 & {X\; 2} \end{matrix}$ Thus, in some examples, the connection between the current prefix unit 720 and the current context unit 755 may be weighted by a weight matrix (e.g., weight factor) X1, the connection between the current stem unit 730 and the current context unit 755 may be weighted by a weight matrix X, and the connection between the current suffix unit 740 and the current context unit 755 may be weighted by a weight matrix X2. The connection between the previous context unit 757 and the current context unit 755 may be weighted by a weight matrix Q. Accordingly, the current context unit 755 may determine the current context value h_(t) in accordance with the following formula: h _(t) =F{P·w _(t) +Q·h _(t−1)} where F{ } denotes a function (e.g., activation function), such as a sigmoid function, a hyperbolic tangent function, a rectified linear unit function, any function related thereto, or any combination thereof. The current context value h_(t) may be provided as a vector of dimension H.

Thereafter, the current context value h_(t) may be provided to the output layer 760, which may in turn provide representations p_(t+1), s_(t+1), and f_(t+1) for a next word based on the current context value h_(t). In particular, the next prefix unit 770 may determine the representation p_(t+1), the next stem unit 780 may determine the representation s_(t+1), and the next suffix unit 790 may determine the representation f_(t+1). Representations p_(t+1), s_(t+1), and f_(t+1) may correspond to potential prefixes, stems, and suffixes of the next word respectively. The representation p_(t+1), for instance, may indicate a probability of each prefix of a predetermined set of prefixes. Each probability may indicate a likelihood that a corresponding prefix is a prefix of the next word. The representation s_(t+1) may indicate a probability of each stem of a predetermined set of stems. Each probability may indicate a likelihood that a corresponding stem is the prefix of the next word. The representation f_(t+1) may indicate a probability of each suffix of a predetermined set of suffixes. Each probability may indicate a likelihood that a corresponding suffix is a suffix of the next word.

Consider, for example, an instance in which the most likely next word is “prepositions,” having a prefix of “pre”, a stem of “posit”, and suffixes of “ion” and “s”. Accordingly, element 772 of the representation p_(t+1) may indicate a high probability of the prefix “pre”, element 782 of the representation s_(t+1) may indicate a high probability of the stem “posit”, and elements 792 and 794 of the representation f_(t+1) may indicate a high probability of the suffixes “ion” and “s”, respectively. It will be appreciated this is description is intended to be exemplary and that, while not shown, other morphemes may also be indicated as having a high probability and the determined next word may be provided as described herein.

In some examples, the connection between the current context unit 755 and the next prefix unit 770 may be weighted by a weight matrix Y1, the connection between the current context unit 755 and the next stem unit 780 may be weighted by a weight matrix Y, and the connection between the current context unit 755 and the next suffix unit 790 may be weighted by a weight matrix Y2. Accordingly, the prefixes p_(t+1), stems s_(t+1), and suffixes f_(t+1), may be determined in accordance with the following formulas: P _(t+1) =G{Y ₁ ·h _(t)} s _(t+1) =G{Y·h _(t)} f _(t+1) =G{Y ₂ ·h _(t)}, where G{ } denotes a function, such as a softmax activation function or any function related thereto.

The candidate prefixes, stems, and suffixes may thereafter be provided to identify one or more next words. The prefixes, stems, and suffixes may, for instance, be provided to a canonical validation module, such as the canonical validation module 610 of FIG. 6 to determine or one or more valid next words, as described.

FIG. 8 is a flow diagram illustrating process 800 for text prediction in accordance with some embodiments. Process 800 is performed, for example, using one or more electronic devices (e.g., 100, 300, or 500) and or text prediction systems disclosed herein (e.g., text prediction system 600). Process 800 is further performed, for example, using a text prediction architecture implemented on the one or more devices (e.g., text prediction network 700 in text prediction module 600 of the device). Operations in process 800 are, optionally, combined and/or the order of some operations is, optionally, changed. Further, some operations in process 800 are, optionally, omitted and/or combined with one or more additional operations.

At block 805, the electronic device receives a current word.

At block 810, the electronic device determines a context (e.g., word history) of the current word based on the current word and a context of a previous word.

At block 815, the electronic device determines a likelihood of a prefix based on the context of the current word. The likelihood of the prefix may be determined using a morpheme-based language model in some examples. In some examples, the prefix is a first prefix and the electronic device determines a likelihood of a second prefix. In some examples, the prefix is an empty prefix.

At block 820, the electronic device determines a likelihood of a stem based on the context of the current word. The likelihood of the stem may be determined using a morpheme-based language model in some examples.

At block 825, the electronic device determines a likelihood of a suffix based on the context of the current word. The likelihood of the suffix may be determined using a morpheme-based language model in some examples. In some examples, the suffix is a first suffix and the electronic device determines a likelihood of a second suffix. In some examples, the suffix is an empty suffix.

In some examples, the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix are determined, at least in part, concurrently.

At block 830, the electronic device determines a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix. In some examples, this includes predicting a next word of a sentence or a completed version of a current word. In some examples, determining a next word based on the likelihood of the prefix, the likelihood of the stem, and the likelihood of the suffix comprises concatenating the prefix, stem, and suffix. In some examples, the electronic device determines the next word based on the likelihood of the second prefix. In some examples, the electronic device determines the next word based on the likelihood of the second suffix.

At block 835, the electronic device provides an output including the next word. In some examples, providing the output including the next word includes displaying the next word on a display of the electronic device.

In some examples, the electronic device determines whether the next word is valid. In some examples, the electronic device determines whether the next word is valid. In some examples, determining whether the next word is valid includes determining whether the next word is included in a lexicon (e.g., lexicon corresponding to a language of the next word).

The operations described above with reference to FIG. 8 are, optionally, implemented by components depicted in FIG. 1A-1B, 3, 6, or 7. For example, receiving operation 805, determining operations 810, 815, 820, 825, and 830, and providing operation 835 are, optionally, implemented by text prediction engine 605, canonical verification engine 610, candidate ranking engine 615, text prediction network 700, or any combination thereof. Similarly, it would be clear to a person having ordinary skill in the art how other processes can be implemented based on the components depicted in FIGS. 1A-1B, 3, 6, and 7.

FIG. 9 is a flow diagram illustrating process 900 for text prediction in accordance with some embodiments. Process 900 is performed, for example, using one or more electronic devices (e.g., 100, 300, or 500) and or text prediction systems disclosed herein (e.g., text prediction system 600). Process 900 is further performed, for example, using a text prediction architecture implemented on the one or more devices text prediction network 700 in text prediction module 600 of the device). Operations in process 900 are, optionally, combined and/or the order of some operations is, optionally, changed. Further, some operations in process 900 are, optionally, omitted and/or combined with one or more additional operations.

At block 905, the electronic device receives a current word representation (e.g., current word vector representation). In some examples, the current word representation includes a current prefix representation, a current stem representation, and a current suffix representation. In some examples, the electronic device receives a current word and encodes the current word to provide the current word representation. The encoded word may be encoded based on grammatical morphemes and/or data-driven morphemes to provide the current word representation in some examples. In some examples, encoding the current word includes identifying a stem of the current word and providing the current stem representation based on the identified stem.

At block 910, the electronic device determines a current word context (e.g., current word context vector representation) based on the current word and a previous word context. In some examples, determining the current word context based on the current word and a previous word context further comprises determining the current word context using an activation function. The activation function is a sigmoid function, a hyperbolic tangent function, a rectified linear unit function or a combination thereof in some examples.

At block 915, the electronic device determines a next word representation based on the current word context. The next word representation includes a next prefix representation, a next stem representation, and a next suffix representation in some examples. In some examples, the next prefix representation is indicative of a plurality of prefixes. In some examples, the next suffix representation is indicative of a plurality of suffixes.

At block 920, the electronic device provides the next word representation. In some examples, providing the next word representation includes providing the next word representation using an output layer of a neural network.

In some examples, the electronic device determines a first word based on the next word representation, determines whether the first word is a valid word, and in accordance with a determination that the first word is a valid word, provides the first word.

In some examples, in accordance with a determination that the first word is not a valid word, the electronic device forgoes providing the first word, determines a second word based on the next word representation, determines whether the second word is a valid word, and in accordance with a determination that the second word is a valid word, provides the second word.

In some examples, the previous word context is associated with a first time step and the current word context is associated with a second time step different than the first time step.

The operations described above with reference to FIG. 9 are, optionally, implemented by components depicted in FIG. 1A-1B, 3, 6, or 7. For example, receiving operation 905, determining operations 910, 915, and providing operation 920 are, optionally, implemented by text prediction engine 605, canonical verification engine 610, candidate ranking engine 615, text prediction network 700, or any combination thereof. Similarly, it would be clear to a person having ordinary skill in the art how other processes can be implemented based on the components depicted in FIGS. 1A-1B, 3, 6, and 7.

In accordance with some implementations, a computer-readable storage medium (e.g., a non-transitory computer readable storage medium) is provided, the computer-readable storage medium storing one or more programs for execution by one or more processors of an electronic device, the one or more programs including instructions for performing any of the methods or processes described herein.

In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises means for performing any of the methods or processes described herein.

In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises a processing unit configured to perform any of the methods or processes described herein.

In accordance with some implementations, an electronic device (e.g., a portable electronic device) is provided that comprises one or more processors and memory storing one or more programs for execution by the one or more processors, the one or more programs including instructions for performing any of the methods or processes described herein.

The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the techniques and their practical applications. Others skilled in the art are thereby enabled to best utilize the techniques and various embodiments with various modifications as are suited to the particular use contemplated.

Although the disclosure and examples have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosure and examples as defined by the claims. 

What is claimed is:
 1. An electronic device, comprising: one or more processors; a memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for: receiving a current word; determining a context of the current word based on the current word and a context of a previous word; determining, using a morpheme-based language model, a first representation indicating a likelihood of each prefix of a predetermined set of prefixes, wherein the likelihood of each prefix is determined based on the context of the current word; determining, using the morpheme-based language model, a second representation indicating a likelihood of each stem of a predetermined set of stems, wherein the likelihood of each stem is determined based on the context of the current word; determining, using the morpheme-based language model, a third representation indicating a likelihood of each suffix of a predetermined set of suffixes, wherein the likelihood of each suffix is determined based on the context of the current word; determining a next word based on the first representation, the second representation, and the third representation; and providing an output including the next word.
 2. The electronic device of claim 1, wherein at least one likelihood of a prefix, at least one likelihood of a stem, and at least one likelihood of a suffix are determined, at least in part, concurrently.
 3. The electronic device of claim 1, wherein determining a next word based on the first representation, the second representation, and the third representation comprises: concatenating at least one prefix, at least one stem, and at least one suffix.
 4. The electronic device of claim 1, wherein the one or more programs further include instructions for: determining whether the next word is valid.
 5. The electronic device of claim 4, wherein determining whether the next word is valid comprises: determining whether the next word is included in a lexicon.
 6. The electronic device of claim 1, wherein determining a first representation indicating a likelihood of each prefix of a predetermined set of prefixes comprises: determining, using the morpheme-based language model, a likelihood of a first prefix; determining, using the morpheme-based language model, a likelihood of a second prefix, and wherein determining a next word based on the first representation, the second representation, and the third representation comprises: determining the next word based on the likelihood of the first prefix and the second prefix.
 7. The electronic device of claim 1, wherein determining a third representation indicating a likelihood of each suffix of a predetermined set of suffixes comprises: determining, using the morpheme-based language model, a likelihood of a first suffix; determining, using the morpheme-based language model, a likelihood of a second suffix, and wherein determining a next word based on the first representation, the second representation, and the third representation comprises: determining the next word based on the likelihood of the first suffix and the second suffix.
 8. The electronic device of claim 1, wherein at least one prefix of the predetermined set of prefixes is an empty prefix.
 9. The electronic device of claim 1, wherein at least one suffix of the determined set of suffixes is an empty suffix.
 10. The electronic device of claim 1, wherein providing an output including the next word comprises: displaying the next word on a display of the electronic device.
 11. A non-transitory computer-readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by one or more processors of an electronic device, cause the electronic device to: receive a current word; determine a context of the current word based on the current word and a context of a previous word; determine, using a morpheme-based language model, a first representation indicating a likelihood of each prefix of a predetermined set of prefixes, wherein the likelihood of each prefix is determined based on the context of the current word; determine, using the morpheme-based language model, a second representation indicating a likelihood of each stem of a predetermined set of stems, wherein the likelihood of each stem is determined based on the context of the current word; determine, using the morpheme-based language model, a third representation indicating a likelihood of each suffix of a predetermined set of suffixes, wherein the likelihood of each suffix is determined based on the context of the current word; determine a next word based on the first representation, the second representation, and the third representation; and providing an output including the next word.
 12. The non-transitory computer-readable storage medium of claim 11, wherein at least one likelihood of a prefix, at least one likelihood of a stem, and at least one likelihood of a suffix are determined, at least in part, concurrently.
 13. The non-transitory computer-readable storage medium of claim 11, wherein determining a next word based on the first representation, the second representation, and the third representation comprises: concatenating at least one prefix, at least one stem, and at least one suffix.
 14. The non-transitory computer-readable storage medium of claim 11, wherein the instructions further cause the electronic device to: determine whether the next word is valid.
 15. The non-transitory computer-readable storage medium of claim 14, wherein determining whether the next word is valid comprises: determining whether the next word is included in a lexicon.
 16. A method, comprising: at an electronic device having one or more processors: receiving a current word; determining a context of the current word based on the current word and a context of a previous word; determining, using a morpheme-based language model, a first representation indicating a likelihood of each prefix of a predetermined set of prefixes, wherein the likelihood of each prefix is determined based on the context of the current word; determining, using the morpheme-based language model, a second representation indicating a likelihood of each stem of a predetermined set of stems, wherein the likelihood of each stem is determined based on the context of the current word; determining, using the morpheme-based language model, a third representation indicating a likelihood of each suffix of a predetermined set of suffixes, wherein the likelihood of each suffix is determined based on the context of the current word; determining a next word based on the first representation, the second representation, and the third representation; and providing an output including the next word.
 17. The method of claim 16, wherein at least one likelihood of a prefix, at least one likelihood of a stem, and at least one likelihood of a suffix are determined, at least in part, concurrently.
 18. The method of claim 16, wherein determining a next word based on the first representation, the second representation, and the third representation comprises: concatenating at least one prefix, at least one stem, and at least one suffix.
 19. The method of claim 16, further comprising: determining whether the next word is valid.
 20. The method of claim 19, wherein determining whether the next word is valid comprises: determining whether the next word is included in a lexicon. 